Rotary drill.



F. B. BocoRsnLs KL ROTARY DRILL.

APPLICATION I'ILED MAY 16, 1914- 1,131,991 Patented Mar. 16, 3915.

rico and State of UNITED STATES PA 'lEN-*1 0FFICE; Fm]: noeensnts'im, or mamas, vmema'.

Romany mum.- I

specificationat new ream.

Patented Mar; 1e; real-l.

Application filed ma m, 1914. Serial No. 839,062.

To all whom it may concern:

Be it known that I, FRANK E. SKI; a citizen of the United States, and residing at Richmond in the county of Hen- Virginia, have invented certain new and useful Improvements in Rotary Drills, of which the following is a specification.

This invention relates to rotary drills, and particularly to the type known as twist drills, and its primary object is to provide a drill which may be reversed end for end to drill from either end. 7

It is well known in the art that drill bits provided with shanks frequently break at the point of juncture between the body of the drill and the shank, thus necessitating discarding, of the drill and causing an appreciable waste. The present invention aims to avoid this loss and expense by providing a reversible drill-bit which is entirely without end projections orshanks, and to effect the rotation of the drill by clamping means applied tothe body of the drill at diametrically-op- Iposite points thereon.

By thus providing a reversible drill, my invention makes it possible to reclaim broken discarded drills which have been rendered useless through the loss of their shanks.

The invention therefore consists broadly of a shankless reversible twist drill-bit.

The invention also includes features of construction which will be fully described hereinafter in connection with the accompanying drawing which forms a part of this specification and the features of novelty of which will beset forth and defined in the appended claim.

In the drawing:

tion of a reversible drill embodying the in-' vention. Fig. 2 is a transverse section on The reference numeral 10 designates a Booonsnn- Figure 1 is a side eleva line XX. From the line X-X at the center of the length of the drill, the groove 13 extends to'the lower point 12 of thedrill, which provides 'a spiral cutting edge 15 extending from the center of the drill to the lower point 12. In other words, the drill is shown with the cutting edge 14 extending from the upper pointed end 11 to the line X-X, and the cutting edge 15 from the line X--X to the lower pointed end 12. As thus constructed, the drill is adapted to be reversed to operate with-a right'hand revolution from either end, and the diametrically opposite flat portions 16 of the body of the drill within the groove'13 are adapted to be engaged by suitable clamping arms or jaws of a. rotating means.- Various rotating devices may be employed for rotating the drill in the manner indicated, but I have the cutting edge 14 is suitably beveled and sharpened to effect the required spiral shearing action, the cutting edge being similarly constructed.

It will be noted that the construction as illustrated in the drawings constitutes substantially two independent drills connected at the point XX integrally to adapt the drill to be readily reversed to make either of its ends available for drilling purposes.

It will be apDarent-thatthe invention enthe point of juncture between the drill and the usual ordinary shank, since I entirely dispense with the shank as a securing means for the drill. It will be also notedthat by my invention, broken discarded drills may be reclaimed by forming a cutting point thereon and adapting them to be engaged at a point intermediate their ends by a suitable clamping device connected with means for rotating the drill.

What I claim as new is A spirally grooved reversible dril1-bit tirely avoids the possibility of breakage at 4 having a spiral cutting edge extending for .In testimony whereofI affix my signature appligximately half ihe length oflthedliit, ang presence of two witnesses. enot er cutting] e ge\ regersey- 'spose with relation to the firet-named spiral-cub FRANK BOCORSELSKI'. 5 ting-edge extending throughout the remain Witnesses;

der 'of the length of the bit, thus adapting RALPH S. COOPER,

' the bit for righb hand drilling at Bithfi]; end. MORRIS Wx Conny. 

